Open AccessImmunogold Localization of the Citrus Exocortis Viroid-Induced Pathogenesis-Related Proteinase P69 in Tomato Leaves
Author(s) -
Pablo Vera,
José Hernández Yago,
Vicente Conejero
Publication year - 1989
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.91.1.119
Subject(s) - immunogold labelling , vacuole , biology , intracellular , viroid , lycopersicon , pathogenesis , botany , microbiology and biotechnology , plant virus , virus , ultrastructure , cytoplasm , virology , immunology
Citrus exocortis viroid induces in tomato plants (Lycopersicon esculentum) synthesis and accumulation of a pathogenesis-related protein (P69) previously reported to be a proteinase (Vera P, Conejero V [1988] Plant Physiol 87: 58-63). By immunogold/transmission electron microscopy, we have studied the distribution of this protein in thin sections of parenchymatous leaf tissue. The enzyme was present intra- and extracellularly. The intracellular location was limited to the vacuole and was always associated with engulfed cell material. When extracellularly located, the enzyme was associated with a dispersed, electron-dense material in the intercellular spaces. This latter location was confirmed after analysis of intercellular washing fluids obtained by vacuum infiltration of leaves. These observations provide new data for the understanding of viroid pathogenesis and the biological role of the pathogenesis-related proteinase P69.